Field of the Invention
The invention relates to an antenna and, more particularly to a directional antenna.
Description of the Related Art
An antenna is an important electronic component in a communication device or a handheld device. Since light, small and thin dimension of the communication device or the handheld devices are welcomed nowadays, the space for the antenna is thus limited.
A planar inverted-F antenna (PIFA antenna) and a monopole antenna are usually common used recently, radiation features of the two antennas are unidirectional, and a radiating pattern is difficult to be changed. In order to meet the requirements of directional features, the antenna needs to be adjusted repeatedly, which increases the time in designing antenna.